Will an epidural steroid injection for bulging disc cause weight gain and water retention.

Not usual: there should not be long term effects from the injections in my experience, but short term possible.

Some basics: Steroid injections allow a focused, higher dose placement of medication directly at the area of need to provide benefit. The medication is used & broken down locally & the amount that enters the general circulation is minimal. When little enters the general circulation there is minimal chance to trigger general side effects like wt gain or water retention.